In the state of the art, many services in the fields of transportation, banking, commerce, telecommunications, or other fields, can be deployed and implemented so they are accessible via access terminals. These access terminals allow access to the service after authenticating a user equipped with a means of access. Typically, with the development of embedded technologies, such a means of access can be a smart card designed for exchanging information with the access terminal.
For example, in the field of banking, an automated cash dispensing service allows a user, via access terminals such as ATMs, to withdraw money using a means of access such as his bank card (conventionally containing a microchip).
Conventionally, the access terminals are connected to at least one central system which manages and supervises the service delivered by the terminals. This connection can be made via a wired connection, a cellular telecommunications network, or some other means, and is established in order to exchange information concerning the service between the server and the access terminals. The central system can thus, for example, retrieve information contained in the means of access, authorize a user to access the service based on the information in the means of access, or order the access terminals to update information associated with a user.
However, this connection between an access terminal and a central server can be complex or even technically unfeasible under certain installation conditions (for example, no coverage by a cellular telecommunications network or a location which does not allow setting up a wired connection). In addition, such connections require installing an expensive infrastructure, limiting the number of access terminals deployed for a service (fewer opportunities for accessing the service).
Document U.S. Pat. No. 6,726,100 discloses a system comprising a plurality of terminals for accessing a service, some of them not connected to said central system. This document describes that the information related to the service can be stored directly on the means of access. Firstly, the stored information is information retrieved by the means of access from the access terminal connected to the central system, which groups information related to the service. In this manner, the unconnected access terminals distribute the service information through data stored in the means of access. Secondly, the means of access can retrieve information contained in a database of an unconnected access terminal, in order to pass on the information for updating in the central system. Thus, the service is correctly provided by the terminals on the basis of data exchanged via the means of access, without necessarily having all the access terminals connected to the central system.
However, the aforementioned means of access generally have a low storage capacity which does not allow retrieving large amounts of information concerning the service. Consequently, for a service that includes for example a large number of users and/or a lot of information for each user, the information provided by the access terminal may be lost or overwritten on a means of access having insufficient storage. Such events are then likely to cause malfunctions in the service, related to incomplete, incorrect, or improperly distributed information.
In addition, the service information contained by the means of access could be accessed and decrypted by a malicious user, thus compromising the security and integrity of the system.